CHEMISTRY TEXTBOOK

Can you recall?

• What is the correlation
  between ionization energies
  and reactivity of elements?


• Trends in ionization energy down a
  group.

Do you know?

First true compound of noble

gas was made in 1962 by Neil

Barteltt and Lohman.

Xe + 2[PtF 6 ] [XeF]⊕ [Pt 2 F 11 ]

Only Xenon reacts directly with

fluorine to form Xenon fluorides.

Remember...

XeF 2 , XeF 4 , XeF 6 are stable

fluoride of xenon.

Xenon also forms compounds with

oxygen, such as XeO 3 , XeOF 2 , XeOF 4 ,

XeO 2 F 2.

Table 7.12 Oxidation states of central halogen

atom in interhalogen compounds.

O.S.

central

Halogen

No. of lone

pairs of

electrons

Examples

+7 0 IF 7

+5 1 ClFIF^5 , BrF^5 ,

5

+3 2 ClFIF^3 , BrF^3 ,

3 , I 2 Cl 6

+1 3

ClF, BrF, IF,

BrCl, ICl,

IBr

Table 7.11 Structures of some Interhalogen Compounds

Formula Name Structure Shape

ICl Iodine monochloride Cl I Cl Linear

ClF 3 Chlorine trifluoride

F Cl F

89 °

F

Bent T- shaped

BrF 3 Bromine trifluoride Br^86 °

F

F

F

Bent T- shaped

BrF 5 Bromine pentafluoride Br

F

F

F

FF

Square pyramidal

ClF 5 Chlorine pentafluoride Cl

F

F

F

FF

Square pyramidal

We have studied earlier in this chapter

that group 18 elements have very high

ionisation energies and due to this property

they are unreactive. Each noble gas atom

has a completely filled valence electron shell

which makes it inert.

The first ionization potential decreases

down the group, hence heavier noble gases

Kr, Xe and Rn can form compounds due to

low ionization energy.

7.13 Compounds of Xenon